1-2 At 45 Now Instead Of 40?
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Northstar Engines and System Technical Discussion Discussion, 1-2 At 45 Now Instead Of 40? in Cadillac Engine Technical Discussion; OK, Maybe I may be going crazy but, My 2001 STS used to shift at redline(roughly 6700rpm) at 40 mph. ...
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    msta293412 is offline Cadillac Owners Fanatic
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    1-2 At 45 Now Instead Of 40?

    OK, Maybe I may be going crazy but, My 2001 STS used to shift at redline(roughly 6700rpm) at 40 mph. This was common for all of us STS owners of this generation. I havent changed anything since Ive noticed this. I already had a slightly modded air intake and slightly modded exhaust, along with 18" factory STS wheels off of the 2006 STS. But the tire height was carefully matched up with a lower profile tire to make it stock specs.....But all this was way prior to this new anomoly. I dont know if the heat around here right now is doing something weird( 94-97 degrees) with rainforest like humidity....I didnt notice this last year, but....Does anyone have any input as to why my car all of a sudden changes gear at WOT of coarse, from 1st to 2nd at 45 mph instaed of 40??....

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    C&C
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    Re: 1-2 At 45 Now Instead Of 40?

    Your PCM may have learned that you do a lot of WOT accelerations and adjusted to your aggressive driving style. The PCM is built to learn, and if you do a lot of one type of driving, may have adjusted itself to try to provide what you are asking for, optimal acceleration.

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    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
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    Re: 1-2 At 45 Now Instead Of 40?

    The red area on a 2001 - 2003 STS tachometer begins at 6,250 RPM. There are no shift speeds listed in the FSM for greater than 50% TPS, so a shift speed of 40-50 is somewhere in the ballpark. It all depends whether you're going uphill, flat, or going downhill. LOTS of factors affect shift speeds. LOTS. .........how many people in the car, for one.......

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    dkozloski's Avatar
    dkozloski is online now Cadillac Owners 10000+ Posts
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    Re: 1-2 At 45 Now Instead Of 40?

    There is also lag and overshoot in the response of analog gauges that can give the appearance of variable results.
    Don't mess with Binky Bear!


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    JimD is offline Cadillac Owners Connoisseur
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    Re: 1-2 At 45 Now Instead Of 40?

    Quote Originally Posted by C&C View Post
    Your PCM may have learned that you do a lot of WOT accelerations and adjusted to your aggressive driving style. The PCM is built to learn, and if you do a lot of one type of driving, may have adjusted itself to try to provide what you are asking for, optimal acceleration.
    I'm pretty sure what was 'learned' is lost when the key is turned OFF.

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    C&C
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    Re: 1-2 At 45 Now Instead Of 40?

    Quote Originally Posted by JimD View Post
    I'm pretty sure what was 'learned' is lost when the key is turned OFF.
    No not lost unless battery power is disconnected; see owners manual.

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    msta293412 is offline Cadillac Owners Fanatic
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    Re: 1-2 At 45 Now Instead Of 40?

    Well guys, all good answers....Though Im sure the pcm would have learned how I drive along time ago, like 3 years Ive owned this thing and I drive it like I stole it. #2 I always do WOT's alone in the car (wife and kids would freak), and I certainly dont race with a freind in the car(dont need any more weight) #3 I live in South Florida(Miami/Ft. Lauderdale) area.....not one hill or small mountain in the entire state(flat as a board) #4 is something to consider as plausible.....The analog gauge can be lagging or slightly inacurate at times....its just that Im noticing this more consistantly now more than ever.....Im going to go with that one untill I can come up with something better. Just a side note though, I always used to run 93, especialy when it cools down around here, the car runs good.....Since the gas prices have gone crazy, I just threw in the towel and started running 87, thinking ok, here comes the heat, that coupled with the 87 octane, my car is gonna be so slow. BUT, for some reason, in the high heat, my car actually runs good WITH the 87, better than the 93. Maybe the 1-2 mph changed when I started running 87 in this hot weather.....I dont know....Thanks for all your input so far......

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